Cider is made by crushing apples into juice and fermenting that juice with yeast, which converts the natural sugars into alcohol and carbon dioxide. The process mirrors winemaking more than brewing, since the fruit provides all the sugar needed for fermentation. While the basic steps are straightforward, each stage offers choices that shape the final flavor, from which apples go into the blend to how the finished cider gets its bubbles.
Choosing the Right Apples
Not all apples make good cider. Eating apples like Gala or Fuji tend to produce juice that’s one-dimensional, mostly sweet with little complexity. Dedicated cider apples bring a balance of acidity, tannin, and sugar that gives the finished drink structure and depth. Cider makers classify apples into four categories based on their acid and tannin content:
- Sweet: Low acid (below 0.45%) and low tannin (below 0.2%). These contribute body and residual sweetness.
- Sharp: High acid (above 0.45%) but low tannin. They add brightness and crispness.
- Bittersweet: Low acid but high tannin (above 0.2%). These are the backbone of many English and French ciders, providing the dry, astringent character that makes cider feel more like wine than juice.
- Bittersharp: High in both acid and tannin. Intense on their own, they add complexity in a blend.
Most ciders are blends. A cider maker might combine a bittersweet variety for tannin with a sharp variety for acidity and a sweet one for fermentable sugar. The goal is a juice that’s balanced before fermentation even begins. In traditional cider regions like Normandy, Asturias, and Somerset, specific local varieties have been cultivated for centuries to fill these roles.
Washing, Sorting, and Milling
The general procedure starts with washing the apples and inspecting them to reject any that are rotten or damaged. This sorting step matters more than it might seem. Tree-picked apples produce juice with no detectable levels of patulin, a mold-related toxin. Apples harvested off the ground, by contrast, can carry significant contamination. Careful culling of bruised or decayed fruit before pressing is one of the most effective safety measures in the entire process.
Once sorted, the apples are milled, meaning they’re ground or chopped into a coarse pulp called pomace. Traditional operations used stone mills or hand-cranked scratters for this. Modern cideries typically use mechanized hammer mills or blade-style grinders that break the fruit down quickly. The goal is to rupture enough cells to release juice without turning the pomace into a paste so fine it won’t press well.
Pressing the Juice
After milling, the pomace is pressed to extract as much juice as possible. The equipment varies by scale and tradition. Small producers sometimes still use rack-and-cloth presses, where layers of pomace are wrapped in fabric and stacked between wooden or plastic racks, then squeezed with a screw or hydraulic mechanism. Commercial cideries more commonly use pneumatic presses, which inflate a rubber bladder inside a cylinder to gently squeeze the pomace against a perforated drum, or horizontal hydraulic presses that apply pressure mechanically. In Asturian cider production, pneumatic presses are by far the most common, though some producers still use hydraulic systems.
The freshly pressed juice is cloudy, full of suspended fruit particles held in place by pectin. At this point it tastes like a particularly complex, slightly tannic apple juice. Its sugar content is typically around 11 Brix, a measurement of dissolved sugar, with roughly twice as much fructose as glucose.
Fermentation
Fermentation is where juice becomes cider. Yeast cells consume the glucose and fructose in the juice and produce ethanol and carbon dioxide as byproducts. The result is a drink that typically finishes at around 5% to 7% alcohol by volume, though this varies with the sugar content of the starting juice.
Cider makers choose between two broad approaches to fermentation. The first is inoculation: adding a selected commercial yeast strain, almost always a variety of the same species used in winemaking and brewing. This gives predictable results and faster fermentation. The second is wild or spontaneous fermentation, where the cider maker relies on the yeast naturally present on the apple skins and in the cidery environment. Countries with deep cider traditions, like France, Spain, Ireland, and Slovenia, have historically favored this wild approach.
Temperature plays a major role in how fermentation unfolds. Warmer fermentation, around 20°C (68°F), can finish in as little as three to four days. Cooler fermentation, closer to 10°C (50°F), slows things dramatically, sometimes taking two weeks or longer to complete. The tradeoff is flavor: slower, cooler fermentations generally preserve more of the delicate fruit aromas from the apples, while warmer fermentations can produce more of the esters and secondary flavors that give cider its complexity. Many traditional producers ferment slowly through the cool winter months for exactly this reason.
Malolactic Fermentation
After the primary fermentation finishes, many ciders go through a second, subtler transformation called malolactic fermentation. This isn’t really a fermentation in the usual sense. Instead, bacteria convert malic acid, the sharp, tart acid that gives green apples their bite, into lactic acid, which is softer and rounder. The result is a cider that feels smoother on the palate with less aggressive acidity. The pH rises slightly as the harsher acid is replaced.
Beyond just softening acidity, this process transforms aroma precursors in the cider into new volatile compounds, adding layers of flavor that weren’t present before. Some cider makers encourage it for the complexity it brings. Others prevent it to preserve a crisp, bright character, especially if they’re working with apple varieties chosen specifically for their acidity. Whether malolactic fermentation happens or not is one of the defining stylistic choices in cider making.
Clarification and Fining
Fresh cider straight from fermentation is hazy. The cloudiness comes mostly from pectin, which forms a negatively charged layer around tiny fruit particles and keeps them suspended in the liquid. Some producers embrace this haze and sell their cider unfiltered. Others want a clear, bright product.
The first step toward clarity is usually adding pectinase, an enzyme that breaks down the pectin holding those particles in suspension. Once the pectin is degraded, the particles clump together and slowly settle to the bottom. To speed this up, cider makers can add fining agents. Bentonite, a type of clay, and chitosan, derived from shellfish shells, are common choices during the juice stage. After fermentation, options expand to include gelatin, isinglass (a protein from fish bladders), and silica gel. Each works slightly differently, but the principle is the same: the fining agent binds to suspended particles, makes them heavy enough to sink, and the clear cider is racked off the sediment.
Carbonation
Still cider exists and has a long tradition, but most commercial cider is carbonated. There are two main methods.
Forced carbonation is the faster, more common approach. Carbon dioxide from a pressurized tank is injected directly into the finished cider until it reaches the desired level of fizz. This is efficient, consistent, and gives the producer precise control over carbonation levels. The vast majority of mass-produced cider is carbonated this way.
Bottle conditioning is the older, slower method. The cider maker adds a small amount of sugar (called priming sugar) to the still or lightly carbonated cider, then seals it in the bottle. Residual yeast in the cider feeds on that sugar, producing a small secondary fermentation inside the sealed bottle. The carbon dioxide has nowhere to escape, so it dissolves into the liquid. This process takes more time and care, but it produces carbonation that many drinkers describe as finer, more integrated, and longer-lasting than forced carbonation. You can often spot bottle-conditioned cider by a thin layer of yeast sediment at the bottom of the bottle.
Sulfites and Preservation
Most cider makers add small amounts of sulfur dioxide at one or more stages of production. Before fermentation, a dose of sulfite knocks back unwanted wild bacteria and molds in the juice while leaving hardier yeast strains to do their work. After fermentation, additional sulfite helps protect the finished cider from oxidation and spoilage during storage. Under U.S. regulations, any cider containing 10 parts per million or more of sulfur dioxide must declare sulfites on the label. Ciders below that threshold don’t require a declaration, and a small but growing number of producers make cider with no added sulfites at all.
From Orchard to Glass
The entire timeline from fresh apples to finished cider can range from a few weeks for a fast, warm-fermented, force-carbonated product to six months or more for a traditionally made cider that ferments slowly through winter, undergoes malolactic fermentation, and is bottle conditioned. Some producers age their cider in oak barrels, adding another layer of flavor and another stretch of time. The pH of the finished product generally falls between 3.0 and 4.2, acidic enough to be naturally resistant to most harmful bacteria, which is one reason cider has been a safe and popular drink for centuries.